Protozoa

Question 1

Giardia lamblia, giardiasis

Answer 1

flagellated protozoan; water and food contamination; anal-oral; ingestion of cysts; worldwide, 1-2 weeks, abdominal pain and bloating, flatulence, greasy diarrhea, treatment: Metronidazole

Question 2

Trypanosoma cruzi

Answer 2

flagellated protozoan, transmitted via kissing bug, South America;

Question 3

Chagas Disease

Answer 3

caused by Trypanosoma cruzi, Romana’s sign, chronic phase for life, enlarged heart, arrythmia, digestive tract problems

Question 4

Toxoplasma gondii

Answer 4

apicomplexan protozoan; definitive host: domestic cat; cysts ingested-cat feves or undercooked meat; worldwide and infection usually sporadic and asymptomatic

Question 5

Cyst general pathway

Answer 5

Cyst -> Oocysts -> tachyzoites (neural, muscle tissue) -> tissue cyst bradyzoites (reactivated for encephalitis)

Question 6

Toxoplasmosis

Answer 6

tachyzoites spread to other organs - brain, lungs, liver, eyes; limited by competent immune system

Question 7

Plasmodium species (Malaria)

Answer 7

apicomplexan protozoan, Definitive host: Anopheles mosquitos, spread during blood meal, endemic to tropic areas

Question 8

Malaria symptoms

Answer 8

2 week intubation; cyclic fever and chills; anemia; affects the most RBC

Question 9

Transmission of helminths

Answer 9

fecal-oral route, penetration of skin, bite by infected blood sucking insect vector

Question 10

Trematodes-flukes

Answer 10

hermaphrodites, eggs develop into larvae and must pass through one intermediate host to be infectious again; develop in intestine, lungs, liver, and blood vessels; develops in snails so humans are infected through water

Question 11

Schistomsoma species

Answer 11

trematode-“blood fluke”; male and female worms joined together; Definitive host-humans; intermediate: snails; mature in liver; causes schistosomiasis

Question 12

Schistosomiasis

Answer 12

Acute: swimmer’s itch- pruritic popular rash usually on legs and feet, site of cercariae penetration;
Chronic intestine: abdominal pain, poor appetite, diarrhea

Question 13

Cestodes- tapeworms

Answer 13

Scolex, suckers attach to intestinal wall; acquired by eating undercooked or raw meat; relatively harmless

Question 14

Taenia solium

Answer 14

tapeworms; scloex: head with suckers/hooks for attachment to intestines; Defintive host: humans, ingestion of cysts; Intermediate hosts: pigs

Question 15

Nermatodes: roundworm

Answer 15

sexes are separate; most species liberate fertilized eggs from host; some are highly specific to humans; other require non-human animal host

Question 16

Necator americanus

Answer 16

“Hook worms”, roundworm; Definitive host: human-only; direct penetration fo skin by larvae; penetrate through feet to blood to lungs to GI tract